This invention relates to high density connectors, which as used herein are connectors having adjacent electrical conductors at very low center line spacings, and to the method of manufacture. Typical harness assemblies, as known in the electrical connector industry, may comprise a flat ribbon cable of discrete wires having insulation thereabout to isolate each wire from an adjacent wire. Each end of each discrete wire is terminated to an electrical connector housing, such as by a procedure known as insulation displacement (I.D.), or by crimping to a metal contact positioned within such housing. In the former case, the I.D. connector includes a V-shaped notch with prongs which insert in the polymeric, insulation material to pierce the insulation of the conductors for electrical termination. This type of connector has been utilized mainly for extruded cable imbedded in polymeric material since the center-to-center spacing of the conductors in such a method and construction may be accurately fixed in a manner that the prongs of the connector spaced likewise reliably pierce the conductors.
With both crimping and I.D. terminating, the wire is individually terminated to a contact member. As a consequence of the physical mass of such contacts, and the need to isolate adjacent contacts, the spacings therebetween were rather broad. One approach to decrease such spacings was to stagger the rows of contacts into two or more rows. Even then the spacings could not be reduced to less than about 25 mils or 0.025 inches.
With the trend toward miniaturization, particularly the rather fine circuitry of PC boards, a centerline spacing of 25 mils by conventional techniques was unacceptable. To further complicate the situation there are inherent limitations on wire, i.e. conductor size. That is, as the need for centerline spacing decreases, there is a concurrent need to reduce the wire size or diameter. To satisfy the latter requirement woven wire mesh was devised as a way to fabricate a connector assembly. U.S. Pat. No. 4,741,707 to Mondor, III, teaches a woven structure for terminating a woven cable, such as by insulation displacement, to an IDC connector. Even with this arrangement, the limitations noted above persist.
U.S. Pat. No. 3,447,120 to Rask, et al. teaches a high-frequency transmission line formed by plural layers of flat woven cables. But again, limitations exist by virtue of the fact that termination of the wires is to individual pins. Another approach is taught in U.S. Pat. No. 3,736,366 to Wittenberg. The patent relates to a tape cable structure having several sets of twisted wire pairs, in parallel relationship, which are laminated so that the twist points are in a fixed phase relation with each other. Each such pair is then terminated to a terminal block. A further but early effort to develop a woven circuit device is taught in U.S. Pat. No. 3,371,250 to Ross, et al. But, as with the later devices, the conductor wires are individually terminated.
The present invention, by a method and construction to be described hereinafter, avoids the inherent limitations imposed by individual wire termination, and hereby is able to achieve a very fine centerline spacing for conductor wires. Such method and construction will become apparent for the description which follows.